This is the secretary of state's second visit in four months, itself following a high-level visit two weeks ago by Robert Gates, U.S. secretary of defense. This time Clinton is in town for the East Asia Summit.

That the two nations have put aside past grievances is well known. Likewise, many Vietnamese have put the hostilities behind them. As a sign of this, in 2008, the foreign press reported that some Hanoians, allegedly including his former jailer, said they would have voted for John McCain in the presidential election, if only they could.

McCain was shot down over Hanoi during the Vietnam War and spent six years as a prisoner of war. He later pushed for normalization of relations, leading to a bilateral trade agreement that helped fuel Vietnamese rapid economic growth — hence, the affection.

But this year has seen an all-systems-go approach to the improvement of ties. There have been the visits by Clinton and Gates, the 15th anniversary of normalization of relations, the first defense talks held in August and stopovers by U.S. war ships.

Clinton’s visit, which is her sixth to the region as America's chief diplomat, underscores the “forward deployed nature of U.S. re-engagement,” said Professor Carlyle Thayer, a Vietnam expert at the University of New South Wales in Australia. He said the interactions were at an “unparalleled level.”

But that's not to say that the two countries don't still harbor some disagreements, especially over human rights, a potentially awkward topic for diplomacy.

Just prior to the current summit, Vietnam arrested two bloggers and continued to hold a thirdafter he had completed his two-and-a-half-year sentence. Three labor activists were also sentenced, one to nine years in jail.

This is something Clinton will have to mention at the summit. Four months ago she brought up human rights issues and internet freedom.

The U.S. embassy expressed its “concern” about the recent arrests in a note posted on its website on Oct. 27. “These actions … contradict Vietnam’ s own commitment to internationally accepted standards of human rights. We urge the government of Vietnam to release these individuals.”

Condemning the actions of the host country will likely not go over well, and both sides know it.

But especially in Vietnam, human rights issues are an integral part of U.S. diplomacy. For Clinton not to address these events would be an oversight. Clinton has previously mentioned that defense cooperation between the nations, still in an early phase, would likely not proceed without human rights improvements.

Driving these concerns is a large Vietnamese-American population, which is especially outspoken about human rights abuses. The Vietnam Reform Party Viet Tan, which is banned in Vietnam, has its headquarters in the United States and pushes strongly for improvements on human rights and democracy.

U.S. Senator Barbara Boxer of California — home to many overseas Vietnamese — has also asked Clinton to bring up human rights at the East Asia Summit.

But the rights issue is potentially divisive within Vietnam's ruling Communist Party, where — despite a desire to present a united front — factions compete for influence. As the country prepares for its 11th Party Congress in January, an event that will decide policy and key positions for the next five years, experts says that factions eager for warmer relations with the U.S. are currently struggling for power against those who prefer closer ties to China.

Forcing Clinton into a position where she must comment on human rights issues and thus threaten stronger ties would, some argue, help the pro-China faction. In terms of human rights, democracy and internet freedoms, the Vietnamese government has long watched China closely.

Yet despite their similarities in dealing with dissent, the Vietnamese also harbor deep distrust of their large neighbor to the north. China occupied Vietnam for over a thousand years, and the nations last fought a war in 1979 on the border they share.

Indeed, analysts regard warmer U.S.-Vietnam ties as the result, in part, of a mutual interest in containing China.

In recent months, the U.S. has come to Vietnam's defense diplomatically, standing up to China's increased assertiveness in the long-standing dispute over possession of the oil-rich Spratly and Paracel archipelagos. Vietnam and China (as well as the Philippines and Indonesia) claim overlapping territories among these South China Sea islands.

“The US will stand up to China in response to regional concerns over Chinese assertiveness in the South China Sea. US-Vietnam relations extend well beyond a single issue focus on China,” says Thayer.

Given these broader, mutual interests, human rights — while an awkward topic – may prove a mere bump in the road.